Q: WHY ARE MY PHOTOS SHRINKING?

I've inserted four medium sized photos from my library, with small captions, using visual, not html. When previewed, each photo is smaller than the preceding one in the column. Also, even though I've clicked SAVE DRAFT, my drafts have been dumped several times, leaving only a single uploaded photo. ~eric. (using osx 10.7.4 and safari 5.1.7)
Blog url: http://meridagoround.wordpress.com/

Advice:
When you start a new post, add the title, set it to private and then publish it. When you are done with the post, set it back to publish and update it. The problem with posts disappearing when saved as a draft has been around for a while, but only seems to hit a small number of people randomly.

The other choice is to get and use an offline blog client such as Windows Live Writer (Windows) or Ecto (Mac) and then everything is saved on your computer and when you are done with the post, you actually publish it directly from the blog client software. See here for offline blog editors so you don't have to go through this again http://en.support.wordpress.com/xml-rpc/

Many thanks for your clear instructions, and kind support. I'm vexed. WP is stalling for me. I've quit safari and quit firefox, and then done a restart, yet wp is responding only in part on either browser. When I attempt to insert media, nothing happens. And I'm unable to get to an earlier revision, as directed. (When I clicked Screen Options nothing drops down from the menu.)

I'm getting the feeling that wp isn't very compatible with mac osx 10.7.4. Is there evidence of this? I deeply want your platform to work for me. But please spare me the pain if it's not up to it. Sorry I have nothing to show, but until I can insert media onto a new post (tried, failed) there is little I can think to do. ~eric.

Ok. I've published this rag for your careful scrutiny. (How embarrassing.) As you will notice, the photos are irregular in size, and jagged in alignment.

And the size itself is less than optimal: termed medium, it is too small; but tried as large, too big. Oddly, there is 'full size' which is said to be (measured in pixels) exactly the same as large. I wish there were a 'medium large.'

Also, the type is misbehaving. While it is all the same while composing, it goes wild when viewed. Italic, bold, etc, when I've simply gone with default.

1) The code of all the images is messed up: you need to delete everything and re-do the post. Captioned images are very sensitive: after you insert a captioned image, make sure the cursor is outside the caption area[*] before doing anything else, and never try to highlight the caption to change its styling via any of the editor tools.

[*] That's very difficult in the Visual editor when the image alignment is set to left: set it to none.

2) Full-size means the widest that can fit in the theme you're using (if the original is larger). The other three options (thumbnail, medium and large) are supposed to be three different pre-set sizes: you are free to adjust these sizes in Settings > Media.